Temporary wharf paves the way for harbour resilience

Tuesday, 31 October 2023

Building a temporary wharf has significantly reduced the cost of the Petone to Ngāurānga shared path.

Wellington Harbour has two new islands and a temporary wharf. Eagle-eyed commuters travelling between Petone and Ngāurānga would have spotted the islands, referred to as offshore habitats by Waka Kotahi, which are part of the Ngā Ūranga ki Pito-One section of Te Ara Tupua.

Construction started on the $312m Petone to Ngauranga shared path and seawall in March and Waka Kotahi regional manager infrastructure delivery Jetesh Bhula said work was progressing well.

The offshore habitats provide a place for birds to land and roost, away from construction activity and were built early in the project to meet the environmental requirements of the resource consent.

A barge did the heavy lifting for the offshore islands.

The islands feature four concrete tidal pools, designed to mimic tidal rocky pools.

The most obvious aspect of construction is a temporary wharf, opposite the BP petrol station on State Highway 2.

Its name, Karanga Landing, acknowledges the original name of the site Pari Karangaranga, meaning the Cliff of Echoes.

It references Māori passing along the gravel beaches, with its lofty rocky cliff towering above them and listening to the voice of a wairua, or spirit, in the heights as this was believed to be the voice of a woman.

Bhula said using a temporary wharf had reduced the time frame by up to nine months, resulting in “significant” cost savings.

One of the offshore islands created as part of the Petone to Ngāurānga shared path and seawall.

Its location was chosen after the area was “scoped” by project ecologists who did an underwater survey looking for an area that would have the least impact on marine life.

The wharf would be completely removed, once construction is finished.

With work on the wharf now finished, work hadstarted on making the project resilient.

Work on the embankments and walls had started in both directions, which would reduce the threat of storms/waves damaging the shared path, Bhula said.

The project has not been without controversy. In September, The Post reported that construction had stopped, following the death of three penguins. The Department of Conservation is investigating the deaths and a prosecution is possible.

More about the project

The shared path is 4.5km long with a 5m sealed surface on the seaward side of the railway line. It is expected to be finished by 2026.
Sloping embankments (known as revetments) built of either boulders or concrete armour units, will protect the shared path, road and rail line from erosion by waves. The design allows for it to be built on to in the future to adapt to climate change and the rising harbour level.
The project is part of a bigger project, known as Te Ara Tupua, which will eventually make it possible to safely cycle/walk from Wellington to Eastbourne.
Waka Kotahi estimates that 2100 cyclists will use the path daily by 2030, as well as 360 runners or walkers and 290 trips on e-scooters.